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I am adding a Mini-Split AC to my house.

Ductless High Wall Mounted Split Air Conditioning and Heating System. Variable Speed DC Inverter Operation Mode: Cooling and Heating. Capacity: 9,000 BTU/Hr. (3/4 Ton) Efficiency Rating: 23.5 S.E.E.R. Electrical Specification: 208-230 VAC, 1 Phase, 60 Hertz.

Current Configuration:

I currently have two AC dedicated circuits to two units.

Main Panel shows

1st two pole breaker as (2 30 amp)

2nd two pole breaker as (2 50 amp)

Both have a distinct ac disconnect box at the condenser.

Question: can either of these lines be used to supply power for the additional Mini-Split or will I need a dedicated line.

Reason for asking is the location of additional mini-split will adjacent to the two units and will be fairly far from the main circuit box for the whole house.

I have the power usage of each of the AC Units in the image included.

Any info would be appreciated.
 

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Electrician
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What size is the wire coming into that disconnect you have pictured?

Is it the circuit supplied by the 50A breaker?

Also, what are the MCA (minimum circuit ampacity), and OCP (over current protection) for the new minisplit?
 

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All the info you gave is fine, but you left out the only important thing. The amperages of the new unit. It may be possible, but I would let a qualified electrician handle it.

Also, neither of those condensors should be on a 50A breaker. This is quite clear on the rating labels.
 

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Electrician
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All the info you gave is fine, but you left out the only important thing. The amperages of the new unit. It may be possible, but I would let a qualified electrician handle it.

Also, neither of those condensors should be on a 50A breaker. This is quite clear on the rating labels.
That's what I was getting at. If the numbers add up, he could replace that disconnect with a sub panel and power the existing condenser and minisplit.
 

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That's what I was getting at. If the numbers add up, he could replace that disconnect with a sub panel and power the existing condenser and minisplit.
I think with that 22A MCA unit he might be able to combine then without a panel. Depends on the max breaker for the 9K btu mini-split. I am now thinking it is going to be 20A max so if that's the case then a panel is the only option.
 

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The particular split he's installing is 15 amp max. Technically the minimum ampacity is 7.5 amps - it might be safer to use a 10 amp breaker, might not be. I happen to be getting that exact same unit myself in a few days.

I was planning to install a new circuit with a 15 amp breaker, since that breaker size is available locally while 10 amp is special order.
 

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The particular split he's installing is 15 amp max. Technically the minimum ampacity is 7.5 amps - it might be safer to use a 10 amp breaker, might not be. I happen to be getting that exact same unit myself in a few days.

I was planning to install a new circuit with a 15 amp breaker, since that breaker size is available locally while 10 amp is special order.
Why would you think 10A is "safer"?

The breaker protects the wire, not the appliance. The appliance has it's own internal protection. If it didn't you'd be required to provide it.

It's no different than plugging in a 1A radio into a 20A kitchen counter circuit.
 

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The particular split he's installing is 15 amp max. Technically the minimum ampacity is 7.5 amps - it might be safer to use a 10 amp breaker, might not be. I happen to be getting that exact same unit myself in a few days.

I was planning to install a new circuit with a 15 amp breaker, since that breaker size is available locally while 10 amp is special order.
Did you even consider the startup current requirements ? Did you read the electrical data on the nameplate ?
 

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Electrician
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The particular split he's installing is 15 amp max. Technically the minimum ampacity is 7.5 amps - it might be safer to use a 10 amp breaker, might not be. I happen to be getting that exact same unit myself in a few days.

I was planning to install a new circuit with a 15 amp breaker, since that breaker size is available locally while 10 amp is special order.

The normal rules for OCP don't apply to motors and compressors. It's not uncommon to legally have a smaller wire with a larger breaker.

…and btw I'll wait for the OP to get back with us about the nameplate info.


Sent from my iPhone using Tapatalk
 

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Why would you think 10A is "safer"?

The breaker protects the wire, not the appliance. The appliance has it's own internal protection. If it didn't you'd be required to provide it.

It's no different than plugging in a 1A radio into a 20A kitchen counter circuit.
Ok. I reasoned that maybe during these partial fault conditions you electricians talk about - glowing connections, etc - the breaker might trip instead. That sizing it "down" to closer to the minimum needed would be a little safer. I'll take your word for it.

Did you even consider the startup current requirements ? Did you read the electrical data on the nameplate ?
The normal rules for OCP don't apply to motors and compressors. It's not uncommon to legally have a smaller wire with a larger breaker.

…and btw I'll wait for the OP to get back with us about the nameplate info.


Sent from my iPhone using Tapatalk
This is the unit he's talking about. The nameplate is visible in the last image on the Amazon page. It's the only minisplit in the world with exactly 23.5 SEER/220V/9000 BTU, so this is the one.
http://www.amazon.com/Pioneer-Effic...=1465231380&sr=8-1&keywords=pioneer+23.5+seer
 

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The particular split he's installing is 15 amp max. Technically the minimum ampacity is 7.5 amps - it might be safer to use a 10 amp breaker, might not be. I happen to be getting that exact same unit myself in a few days.

I was planning to install a new circuit with a 15 amp breaker, since that breaker size is available locally while 10 amp is special order.
The label clearly calls for a minimum 30 amp breaker.
 
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